The present invention relates to an apparatus for the sterilization of containers. It has long been known in the field of the beverage-producing industry to sterilize the containers to be filled, in particular before they are filled. To this end, chemical substances such as hydrogen peroxide or peracetic acid were generally used in the past. The drawback of this sterilization is that the chemical substances have to be rinsed out of the containers with sterile water after the respective treatment. In recent years, therefore, there has been a change to carrying out the sterilization of the containers by irradiation, and in particular by irradiation with electrons or charge carriers. In this case undesired radiation, and in particular x-ray radiation, occurs as an undesired side effect. The protection of the environment and, in particular, the operator of the plant from undesired radiation is therefore particularly important. For this purpose a screening is required which does not permit the escape of the types of radiation which occur.
In this case the present practice is for the screening off to be carried out in particular with high-density materials such as lead. On account of its toxicity, however, this material is undesired in the field of foodstuffs and therefore also in an associated packaging machine. In addition, lead is mechanically more vulnerable than other materials. Any damage to the material or simply time-dependent flowing leads to possible leaks and thus to the escape of radiation. In this context the removal of the lead also has to be taken into consideration when dismantling the machine.
Use is therefore also made of sufficiently thick screens of steel and castings with a high degree of mechanical stability and conformity to foodstuffs as a more advantageous screening. In this case too, an unchanged drawback, however, is that a considerable amount of energy is required in order to heat the thick plates. Such a heating is necessary for example before the beginning of the sterilization, since the surfaces of the sterilization plant have to be disinfected beforehand. This can be carried out for example by means of hydrogen peroxide gas at 70° C. In the case of screening plates which are sufficiently thick to ensure the protection of the operator of the plant, a heating requires a considerable amount of energy and long process times.
The object of the present invention is therefore to reduce the energy consumption and the process time in the case of heating at the same time as an extensive screening of radiation and with a high degree of security. In this case surfaces containing lead are to be avoided in the vicinity of packaging material and corrosion of the screening is to be minimized.